Brazil's sugarcane-based ethanol program is"appropriate for replication in many countries,"writes José Goldemberg, secretary of the environmentfor the Brazilian state of São Paulo, in a perspectivearticle in this week's issue of the journal Science.

But an unregulated biofuels boom in Brazil could meanbust for the Amazon rain forest and a vast savannaecosystem known as the Cerrado, environmentalistswarn.

Expanding large-scale agriculture to grow sugarcane,critics say, will worsen the loss of speciesdiversity, water-quality problems, and habitatfragmentation in some of the world's most biologicallydiverse regions.

"The primary concern is that the biofuels push willdirectly or indirectly increase the loss to Brazil'sremaining natural high biodiversity areas, such as theCerrado," said John Buchanan, a senior director forthe U.S.-based nonprofit Conservation International.

Sugar Farming Not So Sweet?

The 740,100-square-mile (1.9-million-square-kilometer)Cerrado region is South America's largest savanna—oneof the richest in the world, in terms of bird,reptile, fish, and insect species.

According to a study published last year in thejournal Conservation Biology, more than 50 percent ofthe Cerrado has already been transformed intopastureland, causing soil erosion, biodiversity loss,fragmentation, and the spread of nonnative grasses.

"Most of the expansion required will affect theCerrado ecosystem and the Amazon, which are alreadybeing destroyed because of cattle ranching and soybeanfarming," said Leonardo Lacerda of the Brazilianchapter of the international conservation group WWF.